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MG MGA - overheating/head blowing

1588/new 1622 head. Runs like a dream but gets hot on the A3 incline nearby (230 fahrenheit). It has a Payen composite gasket - should it be copper ? should I trust the temp Guage ?

Anyone been there, done that and got the teashirt ??


R
Thanks
Roger Walker

Roger, that is hot but if you have the correct percentage of antifreeze in the coolant, then at 230 degrees it is only just getting to the boiling point.

You dont say what your temp gauge reads on level ground and if the temp drops quickly again when you stop climbing the A3. :-)
If your temperature drops rapidly back to the normal range

It is worth checking your temp gauge, I used a kitchen electronic thermometer to check mine. (just make sure you wash it before you put it back in the kitchen drawer)

Most MGAs run between 175 and 195 degrees dependent upon how hard they are being driven, how hot the weather is, if you are driving uphill for long periods etc.

But it is probably worthwhile checking a few things.

If your ignition timing is wrong your engine can overheat so it is definitely worth checking.
Also if your mixture is too weak.

If you have non-original modern design matrix in your radiator (with four staggered tubes instead of the original 3 in-line tubes), then most owners in the UK believe that this could actually cause overheating by restricting airflow through the radiator.

So a few possibilities there for you.

How long is it since your rebuild Roger?

Years ago I rebuilt my 1622 engine and on its first run out it overheated and boiled over.
But the next day it ran much cooler and I think it possibly could just have been a bit tight from the rebuild.

Cheers

Colyn

Colyn Firth

Colyn,
Many thanks for yours here. The car has 30% antifreeze so the plan is to measure how much water is still in the system and then to check the dash thermomenter.The mixture may also be a little weak so that is something else to check.
More anon.
Roger
Roger Walker

The water was down to 5 pints after the latest foray so I have fitted yet another Payen gasket. The system seems to hold only 7 pints which I don't understand since the manuals vary between 9.5 and 10. Is the radiator smaller ?
Yes the temp got up to 230 again and the guage is reasonably accurate. The Swedes rebuilt the engine sometime back and she had covered perhaps 30K before I brought her home and noticed she was losing water. I then fitted the 1622 head which Peter Burgess had converted. Peter is quite clear that the composite Payer is the best option but I am nervous.
We will give it another run tomorrow.
Roger Walker

Drain your radiator and run it with straight water and a wetting agent such as Water Wetter...or even a radiator flushing agent. Antifreeze may increase your boiling point but but it hinders the ability of the water to transfer heat from the engine to the atmosphere. I'll bet you a cup of tea your engine will run at least 20dF cooler.
Gene Gillam

Overheating on load is a sign of running too lean. Try richening the mixture a flat or two on each carb.

I would also be suspicious of any recently fitted radiator - I have seen brand new ones fitted out of the box that have created huge overheating problems. Take a trip to Moto-Build in Egham and get them to have a look at it. With the correct matrix, the car should run at 175-185F all day long regardless of weather and engine load.

Ignore advice to run on plain water. Antifreeze contains anticorrosion additives that prevent your cooling passages gumming up with rust. Water Wetter is snake oil - many engine builders invalidate warranties if is used, including Peter. see here at the bottom of the black box
http://www.mg-cars.org.uk/peterburgess/indexstart.html

dominic clancy

Gene, Dominic, interesting advice thank you - yes she is running a little lean and the plugs perfectly clean - the ignition may be a few degrees retarded too but I am not absolutely sure what the dynamic figure should be. And.... why will she only take seven pints of coolant .... or does she retain 3 pints when I drain her through the rad ?
R
Roger Walker

Roger

Most of us go for about 32 degrees at 3500rpm with the vacuum disconnected. I have a dynamic timing light if you need to borrow. Are you anywhere near me - Fleet?

Steve
Steve Gyles

Steve, VMT for the timing advice. Yes, I am looking after three MGs and couldn't survive without a timing light.
Are owners generally using copper head gaskets ?

Roger
Rowlands Castle
Roger Walker

Dominic,

I'm afraid we're going to have to agree to disagree on the issue of Water Wetter or other types of wetting agents. If you notice, Peter Burgess starts his paragraph off with "Waterless Coolant . In our opinion..." and finishes off with "Water is the best liquid for transferring heat." The first comment isn't scientific, just opinion, and the last comment is definitely proven science.

My suggestion to try straight water to Roger wasn't meant as a drive it all the time with straight water, rather try straight water and see if his engine temperature drops (it will).

Water Wetter (and other types of wetting agents have corrosion preventing additives) and help the engine run much cooler than a water/antifreeze mixture. Snake oil? There are a lot of people swearing by it...and it's used in racing engines as a corrosion preventative and water pump lubricant so I find it hard to believe that it would hurt an engine.

I had a long thread on the BBS about the engine in my Coupe overheating after adding AC. The engine had run cool (190dF) before adding the AC so I know it was in good shape. I tried everything to get the temperature down. The conversion required the use of an MGB radiator because of the water outlet interfering with the generator/compressor so I had bought a new MGB radiator. In desperation after trying almost everything I had the new radiator recored with a high efficiency radiator core as recommended by Barney Gaylord. No help at all...here, it's easier to list each thing that I did:

1. New radiator
2. Recored new radiator with high efficiency core.
3. Thermostat blanking sleeve to prevent water bypassing radiator
4. Inner fender louvers as used in Twin Cam engine compartments.
5. Advanced the timing

The car ran cool below 55 mph, even when sitting in traffic with the A/C on but at higher speeds, i.e., 70 mph the engine temperature kept climbing to 225/230 dF in 80 degree temps.

6. Changed differential from 4.1 to 3.9

No difference at all in temperature and very little change in RPM's at speed.

So...reading thru everything on the internet about engine cooling I noticed the one main component of a cool running engine appeared to be the amount of water to compared to the amount of antifreeze. More water, less antifreeze, cooler running....increased percentage of antifreeze to water, less cooling, so I decided to flush my engine/radiator and see what happened.

I drained the mixture in the engine, flushed it with plain water several times to get as much antifreeze mixture out, then added a bottle of radiator flush and followed their procedure, driving the car for three days with the flush in the system to get out all the crud (if any). Immediately when I started driving the coupe I saw a huge difference in operating temperature. From 225/230dF at 70 mph I was now running 215dF maximum at 70/75 mph. After three days I drained the engine/radiator - there was no rust or crap in the water so the system had been clean to begin with. I then added water and a bottle of Water Wetter (which does contain corrosion preventative and water pump seal lubricants) and my running temps in 90 dF weather are now 195dF with the A/C on at 55mph, climbing to 212dF at 70 mph. My wife and I were out yesterday afternoon/evening and the A/C worked great and the engine ran cool...the first time I've really felt comfortable driving the car.

Water wetter can be used with anti-freeze in colder climates where you need freeze protection...I may even add a bit of anti-freeze here when winter sets in, just in case.

So...until you've been there you shouldn't dismiss something based on "opinion".
Eugene Gillam

Hi there I hope I am wrong try drain on side of engine my was plugged= restricted cooling to cylinders
Martin
sharpeys

Eugene, that's an interesting narrative and while I accept your final analysis, I wonder how much "radflush" affected the final outcome (I am thinking of going that way too). Sharpey, a long while back my A (and my first B) had a tap. I think I may have to act on your advice.

The news here is the A got over the local hill (Butser) and back again - running according to the dash meter at 215F ... and holding onto all its water.

...but still too darn hot !
R

Roger Walker

It has to be the radiator Roger. I will put money on the Swedish owner having it recored to a non MGA core layout. Just 35 miles up the road from you and mine ran today at its normal 172, 175 max.

For starters how thick is the core? Should be 2 inches. If it's any thinner it could account for some of the reduced capacity.

Steve
Steve Gyles

Roger,

I bought my first 1960 MGA in 1965 after reenlisting in the Navy. I was in California and shortly after buying the car received orders to Danang, Vietnam so I had to drive across country to North Carolina to leave it with my sister to drive to school.

Prior to starting the drive I had the car serviced and had the radiator rodded out (yes, you can rod the original radiator cores) since it had been running hot(tish). When I hit the mountains in north California and headed into Nevada it was boiling over every 30 miles or so. I eventually found an old mechanic shop and he suggested flushing the system to see if anything had been dislodged when they rodded the core of the radiator. Filled the radiator with water and flush and headed out into the desert to give it a whirl. The car ran cool enough that we thought we had it licked. Drained the radiator, filled with antifreeze and water and headed out again. I didn't go 30 miles before it was boiling over again. I found a filling station, bought 3 cans of flush, drained the radiator, added the flush and water and headed out. It never boiled over again. When I reached home I drained the radiator, added a small amount of radiator flush and filled the radiator with water...and the car drove happily, engine cool, until my sister wrecked the car while I was overseas.

I know Steve preaches radiator core, radiator core, radiator core but I don't know of many MGA's running his temperature.
Gene Gillam

Gene

Yes, I know I go on about it but I am convinced in my own mind that it's at the 'core' of so many MGA overheating issues. This time last year I was running 175 to 180 rising to 190 under load. which is quite common in the UK. The only thing I have changed is the fan to the 7 blade asymmetric version. This has lowered it by 5Df and appears to have dampened down the variations. i.e. The needle is rock solid at 170 to 172 regardless of dawdling, speeding or climbing. Yet to do a proper queue analysis.

Steve
Steve Gyles

As of 2 years ago I believe I have the same radiator as Steve in my 3 bearing 1800. It works well but normally in the 180 to 190 range so I don't achieve Steve's amazing figures despite living in Scotland rather warm Hampshire.

I did get in a long traffic jam coming home from the recent MGCC MGA North Weekend and the temperature di go up to over 200.

Paul
Paul Dean

This thread was discussed between 08/06/2016 and 13/06/2016

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